package com.lxb.myforum.security;

import java.io.IOException;

import javax.annotation.PostConstruct;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.access.SecurityMetadataSource;
import org.springframework.security.access.intercept.AbstractSecurityInterceptor;
import org.springframework.security.access.intercept.InterceptorStatusToken;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.web.FilterInvocation;
import org.springframework.stereotype.Component;

/**
 * 
 * @author lxb
 *
 */
@Component
public class CustomFilterSecurityInterceptor extends AbstractSecurityInterceptor implements Filter {

	@Autowired
	private CustomInvocationSecurityMetadataSourceService mySecurityMetadataSource;

	@Autowired
	private CustomAccessDecisionManager myAccessDecisionManager;

	@Autowired
	private AuthenticationManager authenticationManager;

	@PostConstruct
	public void init() {
		super.setAuthenticationManager(authenticationManager);
		super.setAccessDecisionManager(myAccessDecisionManager);
	}

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		System.out.println("=========filter init============");
		System.out.println("=========" + filterConfig.getFilterName() + "============");
	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
		FilterInvocation fi = new FilterInvocation(request, response, chain);
		invoke(fi);
	}

	/**
	 * fi里面有一个被拦截的url 调用MyInvocationSecurityMetadataSource的getAttributes(Object
	 * object) 这个方法获取fi对应的所有权限 再调用MyAccessDecisionManager的decide方法来校验用户的权限是否足够
	 */
	public void invoke(FilterInvocation fi) throws IOException, ServletException {
		InterceptorStatusToken token = super.beforeInvocation(fi);
		try {
			// 执行下一个拦截器
			fi.getChain().doFilter(fi.getRequest(), fi.getResponse());
		} finally {
			super.afterInvocation(token, null);
		}
	}

	@Override
	public void destroy() {
		System.out.println("==========filter destroy================");
	}

	@Override
	public Class<?> getSecureObjectClass() {
		return FilterInvocation.class;
	}

	@Override
	public SecurityMetadataSource obtainSecurityMetadataSource() {
		return mySecurityMetadataSource;
	}
}
